Constitutive model for soils under the condition of cyclic loading

The stress-strain relationship of soils is closely related to the stress path. Generally, if the loading stress paths of the soil are enough close to the same their stress-strain relationship must be basically the same. Sequentially, an arbitrary stress path can be transform into another almost similar stress path for which the strain is more easily to be calculated, so that the constitutive model for such soils can be established. On the basis of this idea, a new constitutive model adaptive to the condition of cyclic loading is established. In the model two parameters describing the plastic deformation laws under the conditions of constant stress ratio loading and constant mean stress respectively are introduced and a new criterion of loading-unloading is suggested. The comparison with experimental result shows that the proposed model reasonably reflects the deformation characteristics of soils under the condition of cyclic loading and is simple in form, in which only five parameters of soil property are involved.